SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7af780129c5c6e7036d154fdf3b95a4aa0a8c975fcad9e53308ad41985a22d8' 
  AND token = '/zpT8KD+01Y+URTi4+EO19Pjtmeg5bjtlCrvzJOsL6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}