SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74e66ab70e65d1af9527313bcec3a13fd6fa9fddbb5504b1f1e4b913f38fd016' 
  AND token = 'fGMIDHZ7th0wQhTQpvywz04Smju2VO2qFDqdYy69Ykg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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