SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27ce3062bfac4c2120de67d415c9ab8a5346afbd17de38801cafb5c204488abc' 
  AND token = 'mLpMS4/61/mmzsTngXoNtCKNsOvHCj+6yY1IIzBqVTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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