SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0754fdaed92bfe6b1467548dccefb6239480844453486f87433c951640c9a521' 
  AND token = 'uz+wuIPNNf2c6TcJV/QY2i89fZlngxa18jW6igo/aNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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