SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '657c7d48334ba5945715230c37c52e3341c46149517d147c679848b869d371a7' 
  AND token = 'rKRYR5m8IKCsN245pxXORdQ/rH8EXwdPRfhn9/YTUDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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