SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba8b74801b98c4a3860c6c6d869cfa4357458e16376235d9955cb66684d0e09f' 
  AND token = '+/T5mk7qmIObkN3nzMViRpqcnWvGLeF+GdqAhLBllD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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