SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3243255f5f19fdd7fb01379049bb953fbaaf164ace07fcb47df79fec3053a199' 
  AND token = '74pRjzIO56tgdlz2MlFpf7pwkUDriHk7ktnpMf/3AjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00092

JSON explain

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