SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a18f6a8fee64325563a58726e22c739e5cfdb85a4ab745450733bedf8f3e835e' 
  AND token = 'xmUPXWDJDkmEVBWCC+O9/lOhh1qzDMteLwpNMGBURrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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