SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee2d2ebfaeede9c2ff8026f8ce86ada38ce81c0b26cb4355477974d32d8f527b' 
  AND token = 'gCG/mDbR8OuEwzASzwHiNGY+mMI7gIrwblaVl/sp/vY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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