SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b2a827a16016dd4a571f945bf383fa249106d22d0dcaceafea7871fc15bc58e' 
  AND token = 'g5rBPqXPlDN5ogRe9idn6/DBjB7/P122xiiPN45Ttis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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