SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51405a60cac98961bbc4dc0cc55f333ff47351cdeac19d49022337d3bb0470a4' 
  AND token = 'ut7OJZsvXlMtjOcZlqQLBDSnB4wqwlnfraazIvWJAbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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