SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4b262c7aa4b49c75b3f5c0522c5dd79a241cf4c1f9b9a0af543745838ddbadf' 
  AND token = 'EpVqbZS09B0wVOthKPBx+9dZkDjVY8WafSrsMN2fzCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}