SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6106ef19cead7c1249589696a398309ce3bf83a54727e02033479b59f9730cc5' 
  AND token = 'URTZXpnKzKUVLPOD/84E0Gi3Qra9VYYWmBCYImvRwhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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