SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4212a7656a7bacb92946c8e296bcc26350712db1a137c41ff92bafde225719c4' 
  AND token = 'imSaN8Z8k2NCem8u3usAIRirMCLAgNSULys4oGiyM34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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