SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8b73af8e4803d248b49fd5f7184e300d893bf8a47eebcf02f0b0a80b27669f7' 
  AND token = 'DQ8DK3m4wVxyfl2UccPKgRQxQkd3eB9nhqoS+FTlcxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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