SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f90fba76ee7ac564010188dcc5abf8da5c7525ec6f9850f62fbad1a07b17c42c' 
  AND token = '0oXVGiHKm+ypR1WvLCV6a/KAOIdRhs3I67HOlETz+Ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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