SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '990dbe9d4d19327b47d1426bc645edd2c8f05b3bd39bd9cb8cb09d5f6a7506b9' 
  AND token = 'SPRJnT9AuRR5bTLOKGc8uxQvVo8SbAGlsNHO/P08mGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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