SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3f1b9ee72c2ad46424a7d893fe4b07c1fdd174ba83882dc0b1ea7985ac0667b' 
  AND token = '+hhLUx7B3Qvp/tMwcbwA6XX1zl0myle6GNuVG1q9/Kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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