SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea5004354eb278aea926ca76f490319f9f15413945df9b5b98da23fab3044f47' 
  AND token = 'xsxhYQ7kPRJCIwEpzkP61FQC+gsYRaNq4vczyBur8Rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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