SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '934941efdb7eb20546b9dd73e508f210136c22b25374650feb54070378f7caa5' 
  AND token = 'o6fGNC+zJcWRoH5N/FzEKKjezC05mszteVBWiCX+Slw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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