SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2187700fe2309e28fbaeb1c944640dc6925f6dd208c8288b5540dd7ce66f801' 
  AND token = 'oqzEzlhTyhjuOK/EPMamJv3KpR2hzXGRBcrjfriBn0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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