SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e19c41d8d18a945ecfcb1bcbe8e1f4a8c4918caa6373c4357077f8e9dd5430f' 
  AND token = 'nH+iTc5LxuwkvPzVInzHAMxlHELC/Qe8GJQbscwEkb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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