SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3feabe2fb608eb8d2edce59c18c9dfb98ef0fc7462b40b369af0b86021d32d41' 
  AND token = 'PfcohmGn67nc4lBFAN6Gh6mhoDQBtRJjHhFVplq84/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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