SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f34afb8d2909a2f0bdd5d8a5e6d02308f56cad35fae18ded43cdf09776746c7' 
  AND token = 'ZyTMwDFT4uNbxLroK7Wp+/hWvLklIuOXQsz7bUaRPIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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