SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd683962302e80eb5d605414c48bd3d6d852cb614a7c31d8a7bb73941ce57d36e' 
  AND token = 'jm3q7FvCUQWq3mqZIDWL/oQdwIQwyThrzYlBiEAuQS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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