SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '16b517670464f84c1df469d74df2e5065002684242a72a68802cfe226bfdd848' 
  AND token = 'BivoLKP6HD7FVVA2KgRIuYsjEn9R5V4SA6Z/CGAdBWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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