SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae18a0d69961ae13ff5a7974bd681a345f25a183bfaf339221657733eb9321c7' 
  AND token = 'G5Yx2xhVVx/ZIiwFXPwJL2rh9aNkqbm/fmkQMIoV2Hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}