SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a19cd3a239646974e4230164a611f5de92b4a23f8d173ee40542470c4a158b9b' 
  AND token = 'boCnDDLUact9sK+Wl/XbCy284ODUIvkuDZrdUqYcCMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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