SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bbbc7452f1473f20765fdbd37f6ede2978ba8978e45d08db2c8189f33813ba6' 
  AND token = '3MLKmjW50GgJ6ZPYsrm16BYBwm5dP7/fvK97TOWie6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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