SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '411ab344c438f30318280a0e419b61c3b72e406563e1b2ebb5edcf2f532a6dbf' 
  AND token = 'u5H9k0WPsbSyIuRJfHLWDIVV1Iw21Fdyfc8FK+QD3J4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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