SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75fd4faa4e369fac6b6f8cdc5f91712c2421128afd2ed60f22cb16d56179b147' 
  AND token = 'VvzcL0Qq1InSeE20uAuMYvawpSBRkGWJewy2OJegYdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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