SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2c4e4918b883acb3ac494ddf55fa022101a406d2306c55f3687274560f64b22' 
  AND token = 'm5pRdHjzCVkJpg+yQPYK11eh7wyc43xnIsPLEojLAww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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