SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f97103467184262d28fc608fbc246e2368bd20d03fcf75be1e786b108e6f49e1' 
  AND token = '34sVB0JtBzswkfkhW/DA4tnVHDKHgGit51tjXl7UjKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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