SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51effcd0b6609944dfbfc3b4b3dc3747c02ae5730f3caffeda16d1fc0102dba6' 
  AND token = 'ubx+hUrKurarcXS4Tr24volinCdQK3UlDyECWrpPqP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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