SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a205df9b4c113fd6b3b30a3835fad4fb6af04ba4b0bf990e49c9afc1819e62' 
  AND token = '1scJ8OinqeF9dSoIOrzbLHxtY+gU7LfPwFYADE+rOtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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