SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6acebdf9ccc31f2b0863632002940a17380acb2bb765f166d0604f9174f2a9d7' 
  AND token = '1RA1Un9vKvITBEiYQW602nSQyCeSqrdDYoub1vUAI34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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