SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b0e5ade9d43f92462cd69d0297253c87687478f310fec54be72929feaa6455d' 
  AND token = 'G++8kR5L8/dEp0GRSfYq5wCSPZqBtyUBs+vOgkV9Kq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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