SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '375d425130af4758c599d9cc831f20a093cea7a8ee42a04b1ced7ccbe780379d' 
  AND token = 'e5FvYWR/lR+ulXDfLipYc9RpxroFF93v3PuoTetttig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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