SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35f623dc796669cacc66ed6400f2302a4361f84dfb404cb5f020ef5a7edf317d' 
  AND token = 'bradpVMLcH+H+0CX6KzbzMOSVAs/qkGJTHUly38W2cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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