SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '607c446a67408bbd22f0959294cf28f189653658540975896301270dd61452aa' 
  AND token = 'jE6j6yYfE2aLK7+8ynAGNSpo+Msl5dkBvqfFHkFcTng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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