SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a6890371dcf6b0d61e2b8240f2b790e7dd24ded65b914d2397f54b73fedf95' 
  AND token = 'l63cuSxmJtUxLLSV/ks1rOqzW+Th1xpk2OSR8m0yQZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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