SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fe7145624cb7fe01480607abc39f5bea54fa7171c5bad1da2dea9474cc7a1498' 
  AND token = 'mFZ272S4+0DfIeEiR0uXxM9LHewuRYpk442JMaDd3H0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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