SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ead397a5e106bf904bfc141742fe9df6355836915023c020bd322c724aa2673a' 
  AND token = 'XYmyneIu+FztKJOD6Jfdf4pZWauJth0+Ycs/bxQz6aE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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