SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4149071569143c30bfd968390a017da9a7b7be71d80ab370bf2d3b0c2d61a4d' 
  AND token = 'Fj4MrCGrD6XWFK3FvoGCyISbiDOzmoPgAc0MtwXipBo=' 
  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"
    }
  }
}