SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ddeb501cd1e1f8992bedefb5ccf66aa940d6570afae20f15d71a8de7a17fc6' 
  AND token = 'UCAzYefLcIWLwlrB3Ef/OC7Ett8F2m/Vegps7dlGzoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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