SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a2d67d93553f9111b27ccdb3c1ba96843e77e6a98e69c4ec66de81b34e0bed9' 
  AND token = 'YRNKchZB4rn2Ff5uvGbkUsfdqY1+HHDhCk6VwS6VAv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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