SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3bde2b43c400c8eb501bd67e5e47b2c46690f8bbdddb51e5773361dde34d493' 
  AND token = 'VENSzxeJ05UEp3hpJXatitxZ2CHDQsSC9O7EmFrzf18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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