SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c531d5e2007fe7b76dabb5f5fb2e103826134f7ee1f0b081cd2686249e98eade' 
  AND token = 'Pc6FusZclBmbHNplhOcGYwYkWSsXerxeB1+yK/z79U0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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