SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f8dd97f3e2406ebdf11998f427507460415d527705f5adbba7cc1e7eddcc4272' 
  AND token = 'ORW4kSLn9UabGUMiK3CcRfdCny6bMalyYH633c85ELo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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