SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbd2af2ba3243ce7496ca3642c610e571b1f9d65eba9a2921f82b88f877e8a74' 
  AND token = 'nfdcBQmFaHVszClzcNu5CtxqmVgu6bqe+KjhcMIgRss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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