SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1b94a99e31926acd694e43706b7363f19c961e3eddafe6b602df801045d4457' 
  AND token = 'fBWMvPbYUxEa5pn+e7375lDc2it1fOwVYwD8cfkqHuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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