SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ece56291067b5ec33f9cff5f15c552d164e9326c79b0b80dfd3f5a658d83fe4d' 
  AND token = 'gKKkxFVqbyT8LzCp2XIdDW3N/EvfzlgTAeqEpIJFevo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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