SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd437176b0abd768d77281883d06d03afc3e84206cd23362b90100546a75c7e62' 
  AND token = 'GtAA8stYFgzs0SjNJu1JocKY/gGwS1LWssYiElHEOS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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