SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2045e79fe817d51a5c35d856545a3b74afdb4ba232a2faa46a87e74223db31a2' 
  AND token = 'kCJUGQP3WpCBXym3sFUadxOhXLDRBPBFes21/H0OS5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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