SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a36772b18089f19fec6a21822fac6fac1fbcaef9aba2b4db2038837f4fe4351b' 
  AND token = 'HBR0VA6sFY5ahOfQv3szkMrLdyxWYfroVoHUtcZzS2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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