SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caf68369aefdb8a3315dcea5c08ada627c426639efe4eb5d88ce3f09fb99b397' 
  AND token = 'tL+c1/70bAXL3Gqbnj2j4PivReQyHsT4Oil948OpoKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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