SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b05304a1f76a40f260fcadddf995a11e3a1784b8f260cc4bfd47e9c095491896' 
  AND token = 'zK5I+CJEniYxrLvtZjhnFX5NNnUMZtKmGbQ+3FL4NfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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