SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0550835b001d8d6aec7f90be09f8917a2af407c3b35586f1e3c8f3207bf02c83' 
  AND token = 'JD/G6kdRK1QOHR7h0shzycJeAbhYmIeioQFYdKzBp9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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