SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5e562b865a02e6366a1a888df801c8c74a39b5c22e7f5f9187bafdb55f58877' 
  AND token = 'OlOFmw4zODaw2iJao8HKAhnrqTC4JFBdaYNpSt+Ruhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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