SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6992e517fccf359caba434f6e7726fde7f4bc3387bb1fd5bfae3bfbfc0a7643d' 
  AND token = 'vqcZQYXPILx3h5u+YVmDzbKb5q/EIwiOMhwT1oONkcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}