SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a66e5c50b9724fd0b47f1f685b3c9fa68b112f713cf5b521003d3d077ca99ebd' 
  AND token = 'xzi1/x/ZR2rgVcSxFmMl1YRw3jDK3BYDesLwQYHDNEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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