SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67db632e3a84d161f2fdcad1aa291bb686226a87ae9543c2dd81d30a422b75ca' 
  AND token = 'nGAYfQdUO08ZzBff35JFOAhYwn2aI3kZAFxSAfwj+mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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