SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ba7b5b8ad9910f9b149d658d825e131501a8c144b465109633832568059e7db' 
  AND token = 'agzge8nxrnClDYDrg/rsCZDOepS6EIZeN+I/nzh3Tf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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