SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32fdf2cc560c704ff23fb642faf65384584c637ea164ea948fa3814771ba6296' 
  AND token = 'oPe3HSK+mOKegAOjLDDDnKbe0ea+Tr540XCRn2W/+r4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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