SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4177498d741014c8afd10eadd27fb0713db9a24f0ed5d4c62bdc68e69516bb88' 
  AND token = 'FH8calcbrD7t8O6LiMKgwbzRT2SIgtm+hYRyH0teVr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}